With
the surging development of flexible wearable and stretchable
electronic devices, flexible energy-storage devices with excellent
electrochemical properties are in great demand. Herein, a flexible
Zn-ion battery comprised by hydrated zinc vanadium oxide/carbon cloth
(ZnVOH/CC) as the cathode is developed, and it shows a high energy
density, superior lifespan, and good safety. ZnVOH/CC is obtained
by the in situ transformation of hydrated vanadium oxide/carbon cloth
(VOH/CC) by an electrochemical method, and the intercalation pseudocapacitive
reaction mechanism is discovered for ZnVOH/CC. The co-insertion/deinsertion
of H+/Zn2+ is observed; the H+ insertion
dominates in the initial discharge stage and the high-rate electrochemical
process, while Zn2+ insertion dominates the following discharge
stage and the low-rate electrochemical procedure. An ultrastable reversible
capacity of 135 mAh g–1 at 20 A g–1 is obtained after 5000 cycles without capacity fading. Moreover,
the as-assembled flexible zinc-ion battery can operate normally under
rolled, folded, and punched conditions with superior safety. It is
capable to deliver a high discharge capacity of 184 mAh g–1 at 10 A g–1 after 170 cycles. This work paves
a new way for designing low-cost, safe, and quick-charging energy-storage
devices for flexible electronics.